SOME REGULATING FACTORS IN BACTERIAL 

 METABOLISM 



I. J. KLIGLER 



Department of Public Health, American Museum of Natural History, New York 



Received for publication, July 5, 1916 



Kendall and his co-workers, in a series of investigations, have 

 developed the idea that in the metabolism of bacteria sugar has 

 a sparing effect on the digestion of protein and that, conse- 

 quently, the continuous feeding of sugar to animals would induce 

 a change in the intestinal flora from a proteolytic to an acid 

 forming type. These results on sugar feeding were confirmed 

 recently by Rettger working on white mice and chickens and 

 by Torrey on human typhoid patients. 



In his investigations Kendall used a constant proportion of 

 sugar to peptone (1 per cent of each) in standard nutrient broth. 

 Observations, made in the course of a study on the proteolytic 

 enzymes of the B. proteus, in media in which the concentration 

 of sugar was varied, led me to think, however, that there were 

 other important factors involved in bacterial metabohsm, the 

 actual effects of which were not known. ^ It became quite evi- 

 dent from these and other observations that the relative con- 

 centrations of sugar and peptone were significant ; that different 

 organisms of closely related groups were capable of utilizing 

 varying amounts of sugar, and that the amount of sugar that 

 a particular form could completely ferment varied within limits 

 with the concentration of the other ingredients, especially pep- 

 tone and phosphate salts. The following are the results of a 

 series of preliminary experiments to test more definitely the 

 validity of these observations: 



' Kendall and Walker in an independent investigation of the same problem 

 obtained identical results. 



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